Assessment of Bone Structure in Renal Transplant Recipients: Comparison of Phalangeal Qualitative Ultrasound and Dual X-Ray Absorptiometry

According to the WHO criteria many renal transplant patients display osteopenia or osteoporosis. Dual-energy X-ray absorptiometry (DXA), the standard method to assess bone mineral density (BMD), is not always available. Quantitative ultrasound (QUS) of the phalanx is an inexpensive, mobile, and radiation-free diagnostic alternative. Few data address the correlation of this method with DXA in renal transplant patients. This study assessed the value of QUS compared with DXA to detect changes in bone structure among renal transplant recipients. This cross-sectional study of 42 patients (22 women), of mean age 40.2 ± 11.9 years, mean time since transplantation of 2.8 ± 2.9 years, and mean dialysis time of 8.55 ± 10.26 months, included. DXA for bone mineral densitometry of the hip (neck and total femur) and spine as well as QUS to measure the amplitude-dependent speed of sound (Ad-SOS) in the phalanx. Using DXA, osteoporosis was observed in 19% of all patients: 9.5% in femoral neck, 9.5% in total region of the femur, and 9.5% in the spinal region. The sensitivity of Ad-SOS for osteoporosis diagnosis in the above regions were 100%, 75%, and 25%, respectively; its specificity was 45%, 43%, and 37%, respectively. There was no significant relation between the two methods for diagnosis of osteoporosis in any region. QUS of phalanx can be recommended for osteoporosis screening in renal transplant patients. Those suspected of osteoporosis should be examined by additional DXA measurements in order to establish the diagnosis.